Bandgap start up check

[mike_bihan]

Friends:

How to do dc sweep to find the stable points of this BGR?
Shall I sweep VCC or the output of the OP?

thanks,

 

[ambreesh]

Ramp up the VDD at very slow rate and very fast (step input)
Use uic in tran analysis, and also provide some nodes with intial condition say output of amp is close to vdd.

 

[avinash]

ambreesh what do you mean by uic in tran analysis.
is it a healthy procedure to give initial condition to the o/p of opamp.because on-chip initial voltage on the opamp could be anything at start.

 

[ambreesh]

Dear Avinash,
I want to find out a situation where the IC doesnot work. And see to it that , the startup we use take care of even such a condition.
That is all I am trying to say.

 

[avinash]

dear ambreesh,
you still did not made me clear about "uic in tran analysis".

 

[Vamsi Mocherla]

UIC is use initial conditions. When you run a transient analysis, rather than allowing the circuit to converge at its calculations, you will use the .IC/.NODE commands(I do not exactly recall the terms), to give initial values of 0 V to the critical nodes. So, that is the case when the start up will help you, if it is replicated in reality.

 

[mike_bihan]

Transient simulation can prove proper start up.

More, I want to do DC analysis to find how many stable points we have.

Thanks

 

[Pipeline]

for example
.TRAN XX XX XX UIC
.IC V(XX)=0V
+V(XX)=5v